Positioning method and positioning structure of inhibitor switch

ABSTRACT

To make it possible to facilitate an accurate positioning of an inhibitor switch with respect to an automatic transmission. There is provided a tack-fastening member, which is mounted in advance between a terminal block and a moving block before an inhibitor switch is fixed on an automatic transmission, for tack-fastening the terminal block and moving block at a relatively rotational position to detect a specific shift position of the automatic transmission and for being broken at a set torque. By this tack-fastening member, the moving block is temporarily fastened on the terminal block, and the moving block in the temporarily fastened state is fitted on a manual shaft at the specific shift position. After this, the inhibitor switch is fixed on the automatic transmission, and the manual shaft is rotated to break the tack-fastening member from the temporarily fastened state.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an inhibitor switch and to apositioning method and a positioning structure for mounting theinhibitor switch on an automatic transmission.

[0003] 2. Description of the Related Art

[0004] A positioning method and a positioning structure for an inhibitorswitch of the prior art are described in Unexamined Published JapanesePatent Application No. 8-74978 and shown in FIG. 9 and FIG. 10, forexample. FIG. 9 is a perspective view showing the entirety of theinhibitor switch, and FIG. 10 is a sectional view showing the same.

[0005] As shown in FIG. 9 and FIG. 10, an inhibitor switch 101 isprovided with a terminal block 103, a case 105 and a moving block 107.The terminal block 103 is equipped with a plurality of stationaryterminals 109. The terminal block 103 is equipped with a positioninghole 113. The case 105 is bonded to the terminal block 103 by fusing it.The case 105 is equipped with slots 115 for fastening and fixingpurposes.

[0006] The moving block 107 is equipped with moving contacts 111. Themoving block 107 is rotatably supported by the terminal block 103 andthe case 105. The moving block 107 is equipped with a fitting hole 121to be fitted on a manual shaft 117 of the automatic transmission.

[0007] This inhibitor switch 101 is mounted by fitting the fitting hole119 of the moving block 107 on the manual shaft 117 of the automatictransmission and by fastening the not-shown bolts inserted in the slots115 to the housing side of the automatic transmission. At the time ofmounting this inhibitor switch 101, an adjustment is made to align thedetected position of the inhibitor switch 101 and a specific shiftposition according to the rotation of the manual shaft 117. Thisspecific shift position is located, for example, at a neutral position(or N-position) of the automatic transmission.

[0008] For this adjustment, with the bolts to be fastened in the slots115 being loosened, the entire inhibitor switch 101 is made rotatablewithin the range of the slots 115 with respect to the manual shaft 117.A hole 119 a with width across flats of a positioning jig 119 is fittedon a fitting portion 117 a with width across flats at the leading end ofthe manual shaft 117. Next, the entire inhibitor switch 111 is turned,and the positioning pin 119 b of the positioning jig 119 is insertedinto the positioning hole 113 of the terminal block 103. In this state,the bolts in the two slots 115 are fastened to fix the inhibitor switch101 on the housing of the automatic transmission.

[0009] By the aforementioned fastening work using the positioning jig119, therefore, all the moving block 107 and the terminal block 103 areaccurately adjusted to the N-position of the manual shaft 117, so thatthe inhibitor switch 101 can be reliably fixed in the accuratelypositioned state with respect to the manual shaft 117.

[0010] By the aforementioned positioning method and positioningstructure of the inhibitor switch, however, at the stage to assemble theinhibitor switch 101 with the automatic transmission, the positioningadjustment has to be made by using the positioning jig 119 thereby toraise a problem that the assembling work of the inhibitor switch 101 iscomplicated.

SUMMARY OF THE INVENETION

[0011] An object of the present invention is to provide an inhibitorswitch positioning method and structure, which can assemble an inhibitorswitch in an accurately positioned state with an automatic transmissionwithout any positioning adjustment.

[0012] According to a first aspect of the invention, there is provided apositioning method of an inhibitor switch including a switch housinghaving a terminal block having stationary contacts and a cover, and amoving block fitted on a manual shaft of an automatic transmission andhaving moving contacts for rotating with respect to the switch housing,the inhibitor switch being fixed on the housing of the automatictransmission for detecting the shift position of the automatictransmission electrically from a relative rotational position relationbetween the stationary contacts and the moving contacts in accordancewith the rotation of the manual shaft of the automatic transmission,which comprises temporarily fastening the switch housing and the movingblock in advance, before the inhibitor switch is fixed on the automatictransmission, through easily broken portions to be broken at a settorque, at relative rotation positions for detecting a specific shiftposition of the automatic transmission; fixing the inhibitor switch onthe automatic transmission after the moving block in the temporarilyfastened state was fitted on the manual shaft at the specific shiftposition; and then releasing the temporarily fastened state by rotatingthe manual shaft to break the easily broken portions.

[0013] According to a second aspect of the invention, there is provideda positioning structure of an inhibitor switch including a switchhousing having a terminal block having stationary contacts and a cover,and a moving block fitted on a manual shaft of an automatic transmissionand having a fitting hole and moving contacts for rotating with respectto the switch housing, the inhibitor switch being fixed on the housingof the automatic transmission for detecting the shift position of theautomatic transmission electrically from a relative rotational positionrelation between the stationary contacts and the moving contacts inaccordance with the rotation of the manual shaft of the automatictransmission, which comprises a tack-fastening member fastened betweenthe switch housing and the moving block in advance, before the inhibitorswitch is fixed on the automatic transmission, at relative rotationpositions for detecting a specific shift position of the automatictransmission and adapted to be broken at a set torque, wherein themoving block is brought into a temporarily fastened state with respectto the switch housing; after the moving block in the temporarilyfastened state was fitted on the manual shaft at the specific shiftposition, the inhibitor switch is fixed on the automatic transmission;and the temporarily fastened state is then released by rotating themanual shaft to break the easily broken portions.

[0014] According to a third aspect of the invention, there is provided apositioning structure of an inhibitor switch including a switch housinghaving a terminal block having stationary contacts; and a moving blockfitted on a manual shaft of an automatic transmission and having afitting hole and moving contacts for rotating with respect to theterminal block, the inhibitor switch being fixed on the housing of theautomatic transmission for detecting the shift position of the automatictransmission electrically from a relative rotational position relationbetween the stationary contacts and the moving contacts in accordancewith the rotation of the manual shaft of the automatic transmission,which comprises a tack-fastening member fastened between the terminalblock and the moving block in advance, before the inhibitor switch isfixed on the automatic transmission, at relative rotation positions fordetecting a specific shift position of the automatic transmission andadapted to be broken at a set torque, wherein the moving block isbrought into a temporarily fastened state with respect to the terminalblock; after the moving block in the temporarily fastened state wasfitted on the manual shaft at the specific shift position, the inhibitorswitch is fixed on the automatic transmission; and the temporarilyfastened state is then released by rotating the manual shaft to breakthe easily broken portions.

[0015] In a positioning structure of an inhibitor switch as set forth inthe third aspect of the invention, according to a fourth aspect of theinvention, the tack-fastening member is made of a resin and includes afirst fixed portion to be fixed on the side of the terminal block, asecond fixed portion to be fixed on the side of the moving block, and aneasily broken portion for connecting the first and second fixedportions.

[0016] In a positioning structure of an inhibitor switch as set forth inthe fourth aspect of the invention, according to a fifth aspect of theinvention, the first and second fixed portions are formed into a ringshape generally concentric to the fitting hole of the moving block; andthe easily broken portion is provided in plurality in thecircumferential directions between the first and second fixed portions.

[0017] In a positioning structure of an inhibitor switch as set forth inthe fourth or fifth aspect of the invention, according to a sixth aspectof the invention, the first fixed portion is equipped with an outerpress-fit portion; the second fixed portion is equipped with an innerpress-fit portion; the terminal block is equipped with an outputpress-fitting accommodating portion for press-fitting the outputpress-fit portion; the moving block is equipped with an innerpress-fitting accommodating portion for press-fitting the innerpress-fit portion; and each of the press-fit portions has a crushingstrength set higher than the strength of the easily broken portions.

[0018] In a positioning structure of an inhibitor switch as set forth inthe sixth aspect of the invention, according to a seventh aspect of theinvention, the terminal block is equipped with an inward circumferencefor confronting the outer circumference of the ring-shaped first fixedportion; the moving block is equipped with an outward circumference forconfronting the inner circumference of the ring-shaped second fixedportion; and an accommodating recess for accommodating the first andsecond fixed portions is formed between the inward circumference and theoutward circumference.

[0019] In a positioning structure of an inhibitor switch as set forth inthe sixth or seventh aspect of the invention, according to an eighthaspect of the invention, the first fixed portion is equipped separatelyof the outer press-fit portion with outer fastening portions to befastened and fixed on the side of the terminal block; the second fixedportion is equipped separately of the inner press-fit portion with innerfastening portions to be fastened and fixed on the side of the movingblock; the outer fastening portions are thermally additionally fastenedand fixed on the side of the terminal block; and the inner fasteningportions are thermally additionally fastened and fixed on the side ofthe moving block.

[0020] In a positioning structure of an inhibitor switch as set forth inthe seventh aspect of the invention, according to a ninth aspect of theinvention, the outer press-fitting accommodating portions, the innerpress-fitting accommodating portions and the accommodating recess areopened to the outer faces of the terminal block and the moving block.

[0021] In a positioning structure of an inhibitor switch as set forth inany of the fourth to ninth aspects of the invention, according to atenth aspect of the invention, the easily broken portions are interposedin plurality at different spacings in the circumferential directionsbetween the first and second fixed portions.

[0022] In a positioning structure of an inhibitor switch as set forth inany of the fourth to tenth aspects of the invention, according to aneleventh aspect of the invention, the easily broken portions aregradually thinned from both of the first fixed portion and the secondfixed portion to the others to form stress-concentrated portions attheir intermediate portions.

[0023] According to the first aspect of the invention, there is provideda positioning method of an inhibitor switch including: a switch housinghaving a terminal block having stationary contacts and a cover; and amoving block fitted on a manual shaft of an automatic transmission andhaving moving contacts for rotating with respect to the switch housing,wherein the inhibitor switch is fixed on the housing of the automatictransmission for detecting the shift position of the automatictransmission electrically from a relative rotational position relationbetween the stationary contacts and the moving contacts in accordancewith the rotation of the manual shaft of the automatic transmission. Inthis positioning method, the switch housing and the moving block can betemporarily fastened in advance, before the inhibitor switch is fixed onthe automatic transmission, by easily broken portions to be broken at aset torque, at relative rotation positions for detecting a specificshift position of the automatic transmission.

[0024] Therefore, the relative rotation positions for detecting thespecific shift position of the automatic transmission between the switchhousing and the moving block can be accurately positioned.

[0025] The inhibitor switch can be fixed on the automatic transmissionafter the moving block in that temporarily fastened state was fitted onthe manual shaft at the specific shift position.

[0026] Therefore, it is possible to accurately position the specificshift position of the manual shaft and the relative rotation positionsof the switch housing and the moving block for detecting the specificshift position. In this state, moreover, the inhibitor switch is fixedon the automatic transmission so that the positional relation betweenthe switch housing and the moving block and the manual shaft can beaccurately determined.

[0027] After this, the temporarily fastened state can be released byrotating the manual shaft to break the easily broken portions.

[0028] Therefore, the inhibitor switch can be brought into a using statewithout any special work.

[0029] Thus, at the time of mounting the inhibitor switch, the inhibitorswitch can be accurately assembled with extreme ease with the automatictransmission without any special positioning work using a jig.

[0030] According to the second aspect of the invention, there isprovided a positioning structure of an inhibitor switch including: aswitch housing having a terminal block having stationary contacts and acover; and a moving block fitted on a manual shaft of an automatictransmission and having a fitting hole and moving contacts for rotatingwith respect to the switch housing, wherein the inhibitor switch isfixed on the housing of the automatic transmission for detecting theshift position of the automatic transmission electrically from arelative rotational position relation between the stationary contactsand the moving contacts in accordance with the rotation of the manualshaft of the automatic transmission. In the positioning structure, theswitch housing and the moving block can be temporarily fastened by atack-fastening member to be broken at a set torque, before the inhibitorswitch is fixed on the automatic transmission, at relative rotationpositions for detecting a specific shift position of the automatictransmission.

[0031] Therefore, it is possible to accurately position the relativerotation positions for detecting the specific shift position of theautomatic transmission between the switch housing and the moving block.

[0032] After the moving block in this temporarily fastened state wasfitted on the manual shaft at the specific shift position, the inhibitorswitch can be fixed on the automatic transmission.

[0033] Therefore, it is possible to accurately position the specificshift position of the manual shaft and the relative rotation positionsof the switch housing and the moving block for detecting the specificshift position. In this state, moreover, the inhibitor switch is fixedon the automatic transmission so that the positional relation betweenthe switch housing and the moving block and the manual shaft can beaccurately determined.

[0034] After this, the temporarily fastened state can be released byrotating the manual shaft to break the easily broken portions.

[0035] Therefore, the inhibitor switch can be brought into a using statewithout any special work.

[0036] Thus, at the time of mounting the inhibitor switch, the inhibitorswitch can be accurately assembled with extreme ease with the automatictransmission without any special positioning work using a jig.

[0037] According to the third aspect of the invention, there is provideda positioning structure of an inhibitor switch including: a switchhousing having a terminal block having stationary contacts; and a movingblock fitted on a manual shaft of an automatic transmission and having afitting hole and moving contacts for rotating with respect to theterminal block, wherein the inhibitor switch is fixed on the housing ofthe automatic transmission for detecting the shift position of theautomatic transmission electrically from a relative rotational positionrelation between the stationary contacts and the moving contacts inaccordance with the rotation of the manual shaft of the automatictransmission. The terminal block and the moving block can be temporarilyfastened by a tack-fastening member to be broken at a set torque, inadvance before the inhibitor switch is fixed on the automatictransmission, at relative rotation positions for detecting a specificshift position of the automatic transmission and adapted to be broken ata set torque.

[0038] Therefore, it is possible to accurately position the relativerotation positions for detecting the specific shift position of theautomatic transmission between the terminal block and the moving block.

[0039] After the moving block in this temporarily fastened state wasfitted on the manual shaft at the specific shift position, the inhibitorswitch can be fixed on the automatic transmission.

[0040] Therefore, it is possible to accurately position the specificshift position of the manual shaft and the relative rotation positionsof the terminal block and the moving block for detecting the specificshift position. In this state, moreover, the inhibitor switch is fixedon the automatic transmission so that the positional relation betweenthe terminal block and the moving block and the manual shaft can beaccurately determined.

[0041] After this, the temporarily fastened state can be released byrotating the manual shaft to break the easily broken portions.

[0042] Therefore, the inhibitor switch can be brought into a using statewithout any special work.

[0043] Thus, at the time of mounting the inhibitor switch, the inhibitorswitch can be accurately assembled with extreme ease with the automatictransmission without any special positioning work using a jig.

[0044] In addition to the effects of the third aspect of the invention,according to the fourth aspect of the invention, the tack-fasteningmember is made of a resin and includes: a first fixed portion to befixed on the side of the terminal block; a second fixed portion to befixed on the side of the moving block; and an easily broken portion forconnecting the first and second fixed portions. The relative rotationpositions of the terminal block and the moving block can be temporarilyfastened reliably by the tack-fastening member.

[0045] When the manual shaft is rotated after the assembly, moreover,the second fixed portion on the moving block side rotates with respectto the first fixed portion on the terminal block side so that the easilybroken portion can be broken at the set torque. As a result, theinhibitor switch can be easily brought into the using state. Moreover,the first and second fixed portions and the easily broken portion can beintegrally molded of the resin with ease.

[0046] In addition to the effects of the fourth aspect of the invention,according to the fifth aspect of the invention, the first and secondfixed portions are formed into a ring shape generally concentric to thefitting hole of the moving block, and the easily broken portion isprovided in plurality in the circumferential directions between thefirst and second fixed portions. Therefore, the easily broken portionscan be individually thinned and can be reliably broken at the set torquewhile suppressing their flexibility.

[0047] In addition to the effects of the fourth or fifth aspect of theinvention, according to the the sixth aspect of the invention: the firstfixed portion is equipped with an outer press-fit portion, and thesecond fixed portion is equipped with an inner press-fit portion; theterminal block is equipped with an output press-fitting accommodatingportion for press-fitting the output press-fit portion, and the movingblock is equipped with an inner press-fitting accommodating portion forpress-fitting the inner press-fit portion; and each of the press-fitportions has a crushing strength set higher than the strength of theeasily broken portions. While the tack-fastening member is beingreliably fixed by the press-fitting operation in the terminal block andthe moving block, therefore, the easily broken portions can be reliablybroken without inviting any looseness in the press-fits.

[0048] In addition to the effects of the six aspect of the invention,according to the seventh aspect of the invention, the terminal block isequipped with an inward circumference for confronting the outercircumference of the ring-shaped first fixed portion, and the movingblock is equipped with an outward circumference for confronting theinner circumference of the ring-shaped second fixed portion, and anaccommodating recess for accommodating the first and second fixedportions is formed between the inward circumference and the outwardcircumference. Therefore, the first and second fixed portions areaccommodated in the accommodating recess so that the outer circumferenceof the first fixed portion can confront the inward circumference of theterminal block and so that the inner circumference of the second fixedportion can confront the outward circumference of the moving block.

[0049] When the easily broken portions are broken, therefore, the firstfixed portion and the second fixed portion are to be deformed outwardand inward, respectively. By the inward circumference and the outwardcircumference, however, the first and second fixed portions aresupported and prevented from being deformed to transmit the breakingforce reliably to the easily broken portions thereby to break themaccurately at the set torque.

[0050] In addition to the effects of the sixth or seventh aspect of theinvention, according to the eighth aspect of the invention, the firstfixed portion is equipped separately of the outer press-fit portion withouter fastening portions to be fastened and fixed on the side of theterminal block, and the second fixed portion is equipped separately ofthe inner press-fit portion with inner fastening portions to be fastenedand fixed on the side of the moving block, and the outer fasteningportions are thermally additionally fastened and fixed on the side ofthe terminal block, and the inner fastening portions are thermallyadditionally fastened and fixed on the side of the moving block. Evenafter the easily broken portions were broken, therefore, the first fixedportion can be held on the terminal block, and the second fixed portioncan be held on the moving block, so that the dust can be prevented frombeing accumulated.

[0051] Upon the outer press-fit portions and the inner press-fitportions, moreover, the thermal influences of the thermally additionallyfastening operations of the outer fastening portions and the innerfastening portions can be suppressed to suppress the looseness due tothe thermal influences of the outer press-fit portions and the innerpress-fit portions. Therefore, the easily broken portions can bereliably broken.

[0052] In addition to the effects of the seventh aspect of theinvention, according to the ninth aspect of the invention, the outerpress-fitting accommodating portions, the inner press-fittingaccommodating portions and the accommodating recess are opened to theouter faces of the terminal block and the moving block. Therefore, thetack-fastening member can be easily mounted. Even if the tack-fasteningmember should come after being broken, moreover, it would go out of theinhibitor switch so that it would not trouble the function of theinhibitor switch.

[0053] In addition to the effects of any of the fourth to ninth aspectsof the invention, according to the tenth aspect of the invention, theeasily broken portions are interposed in plurality at different spacingsin the circumferential directions between the first and second fixedportions. At the using time of the inhibitor switch after the easilybroken portions were broken, the intervals, at which the individualbroken faces of the easily broken portions of the first and second fixedportions simultaneously confront in the rotational direction when thesecond fixed portion is rotated with respect to the first fixed portionby the rotation of the moving block accompanying the rotation of themanual shaft, are suppressed only one time for a rotation of 360degrees. At the using time just after broken, even the broken faces ofthe easily broken portions of the first and second fixed portionscontact each other, the states of the simultaneous contacts and nocontact are not repeated so that the fluctuation of the operation torquecan be drastically suppressed.

[0054] In addition to the effects of any of the fourth to tenth aspectsof the invention, according to the eleventh aspect of the invention, theeasily broken portions are gradually thinned from both of the firstfixed portion and the second fixed portion to the others to formstress-concentrated portions at their intermediate portions. When thesecond fixed portion rotates with respect to the first fixed portion,therefore, the shearing stress is concentrated at the stressconcentrated portions of the easily broken portions to break the easilybroken portions easily and reliably at the set torque at the stressconcentrated portions. The broken faces of the easily broken portionscan be easily extended along the directions of the relative rotations ofthe first and second fixed portions. When the second fixed portionrotates with respect to the first fixed portion, the broken faces at theeasily broken portions of the first and second fixed portions can besuppressed from contacting to prevent the fluctuation of the operationtorque more reliably.

BRIEF DESCRIPTION OF THE DRAWINGS

[0055]FIG. 1 is a top plan view of an inhibitor switch to which oneembodiment of the invention is applied;

[0056]FIG. 2 is an enlarged top plan view of an essential portion of theinhibitor switch according to one embodiment;

[0057]FIG. 3 is a sectional view taken in arrows SA-SA of FIG. 2according to one embodiment;

[0058]FIG. 4 is a top plan view of a tack-fastening member according toone embodiment;

[0059]FIG. 5 is a sectional view taken in arrows SB-SB of FIG. 4according to one embodiment;

[0060]FIG. 6 relates to one embodiment, of which:

[0061]FIG. 6A is an enlarged top plan view of an essential portionshowing an easily broken portion;

[0062]FIG. 6B is a sectional view of a stress concentrated portion;

[0063]FIG. 6C is an enlarged top plan view of an essential portion afterthe easily broken portion was broken;

[0064]FIG. 6D is an enlarged top plan view of an essential portionshowing an easily broken portion having no stress concentrated portion;and

[0065]FIG. 6E is an enlarged top plan view of an essential portionshowing the stress concentrated portion broken;

[0066]FIG. 7 is an enlarged top plan view of an essential portionshowing an accommodating portions according to one embodiment;

[0067]FIG. 8 is a sectional view taken in arrows SC-SC of FIG. 7according to one embodiment;

[0068]FIG. 9 is a perspective view of an inhibitor switch according to aprior art example; and

[0069]FIG. 10 is a sectional view of the inhibitor switch according tothe prior art example.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0070]FIG. 1 is a top plan view of an inhibitor switch 1 to which theinvention is applied; FIG. 2 is an enlarged top plan view of anessential portion; and FIG. 3 is a sectional view taken in arrows SA-SAof FIG. 2. As shown in FIGS. 1 to 3, an inhibitor switch 1 is providedwith a terminal block 3, a case 5 and a moving block 7.

[0071] The terminal block 3 is equipped with a plurality of stationarycontacts 9, as shown in FIG. 3. To the terminal block 3, there is bondedthe case 5 to construct a switch housing 10, in which a contactaccommodating chamber 11. The terminal block 3 and the case 5 are bondedat a fused portion 12, for example, by a high-frequency fusing method.Between the terminal block 3 and the case 5, moreover, there issandwiched a rubber seal member 13 such as an O-ring. The case 5 isthermally additionally fastened and fixed on a bracket 15 at fouradditionally fastened portions 14. From two portions of the bracket 15,there are protruded two fixing protrusions 16 and 17, in which fasteningslots 19 and 21 are individually formed.

[0072] The moving block 7 is composed of a boss portion 23 and a contactsupporting disc 25. The boss portion 23 is rotatably supported theterminal block 3 and the case 5. Between the boss portion 23, and theterminal block 3 and the case 5, there is sandwiched a seal member 26made of rubber such as an O-ring. In the boss portion 23, there isformed a fitting hole 24 having a width across flats. This fitting hole24 fits on the manual shaft of an automatic transmission. The contactsupporting disc 25 is extended into the contact accommodating chamber11. A plurality of moving contacts 27 are supported on the contactsupporting disc 25.

[0073] And, the shift position of the automatic transmission can beelectrically detected from the rotational position relations between thestationary contacts 9 and the moving contacts 27 according to therotation of the manual shaft.

[0074] The positioning structure of this inhibitor switch 1 is equippedwith a tack-fastening member 29, as shown in FIG. 1, FIG. 2 and FIG. 3.The tack-fastening member 29 fastens the terminal block 3 and the movingblock 7 temporarily at a specific shift position of the automatictransmission, e.g., at a relatively rotational position for detecting aneutral position (or N-position), for example. Therefore, the terminalblock 3 is provided with an accommodation recess 31, in which thetack-fastening member 29 is accommodated.

[0075] The tack-fastening member 29 is shown in FIG. 4 and FIG. 5. FIG.4 is a top plan view of the tack-fastening member 29, and FIG. 5 is asectional view taken in arrows SB-SB of FIG. 4.

[0076] As shown in FIG. 4 and FIG. 5, the tack-fastening member 29 ismade of a resin such as polyphenylene sulfide (PPS). However, thematerial for the tack-fastening member 29 can be variously selectedaccording to a later-described breaking torque. The tack-fasteningmember 29 is made so symmetric in the thickness direction so that it hasno directivity in the thickness direction.

[0077] The tack-fastening member 29 is equipped with a first fixedportion 33, a second fixed portion 35 and easily broken portions 37connecting the first and second fixed portions 33 and 35.

[0078] The first and second fixed portions 33 and 35 are formed intosuch ring shapes as are generally concentric with the fitting hole 24 ofthe moving block 7. The first fixed portion 33 is fixed on the side ofthe terminal block 3, and the second fixed portion 35 is fixed on theside of the moving block 7.

[0079] From the outer circumference of the first fixed portion 33, thereare protruded a pair of outer fastening portions 39 for fastening/fixingpurposes. The outer fastening portions 39 are made thinner than, thatis, one half as thick as the first fixed portion 33. In the individualouter fastening portions 39, there are formed through holes 39 a. On theouter circumference of the first fixed portion 33, there are also formeda plurality of, e.g., four outer press-fit portions 41 which areprotruded radially outward. On the root side of each outer press-fitportion 41, there are protruded a pair of press-fitting protrusions 43on the two circumferential sides. The spacing between the leading endsof the protrusions 43 is made slightly larger than the width of theouter press-fit portion 41 so that it contributes to the later-describedpress-fitting. The first fixed portion 33 is wholly chamfered at 45.These chamfers 45 make it easy to mount the first fixed portion 33 onthe side of the terminal block 3.

[0080] The second fixed portion 35 is made as thick as the first fixedportion 33, and inner fastening portions 47 for fastening/fixingpurposes are protruded from the inner circumference of the second fixedportion 35. The inner fastening portions 47 are made thinner than, thatis, as thick as the second fixed portion 35. The inner fasteningportions 47 are arranged with a shift of about 90 degrees with respectto the outer fastening portions 39 of the first fixed portion 33.Therefore, the tack-fastening member 29 can be reliably fixed by theouter fastening portions 39 and the inner fastening portions 47 whichare offset by about 90 degrees. In the inner fastening portions 47,there are formed through holes 47 a. On the inner circumference of thesecond fixed portion 35, there are formed a plurality of, e.g., fourinner press-fit portions 49 which are protruded radially inward. On theleading end side of each inner press-fit portion 49, there are protrudeda pair of press-fitting protrusions 51 on the two circumferential sides.The spacing between the leading ends of the protrusions 51 is madeslightly larger than the width of the inner press-fit portion 49 so thatit contributes to the later-described press-fitting. The second fixedportion 35 is wholly chamfered at 53 on its inner circumferential side.These chamfers 53 make it easy to mount the second fixed portion 35 onthe side of the moving block 7.

[0081] The protrusions 43 are arranged on the root sides of theindividual outer press-fit portions 41, and the protrusions 51 arearranged on the leading end sides of the individual inner press-fitportions 49. This is because the individual protrusions 43 and 51 arearranged as close to the center of rotation as possible. With thisarranging construction of the individual protrusions 43 and 51, thedislocations in the circumferential directions can be extremely reducedeven if the individual protrusions 43 and 51 are differently crushedwhen press-fitted, so that the accuracy dispersions can be drasticallyreduced.

[0082] The easily broken portions 37 are provided in plurality atunequal spacings in the circumferential directions between the first andsecond fixed portions 33 and 35. The easily broken portions 37 areformed, as shown in FIG. 5 and FIG. 6A. FIG. 6A is an enlarged top planview of an essential portion showing the easily broken portion; FIG. 6Bis a sectional view of a stress concentrated portion; FIG. 6C is anenlarged top plan view of an essential portion after the easily brokenportion was broken; FIG. 6D is an enlarged top plan view of an essentialportion showing an easily broken portion having no stress concentratedportion; and FIG. 6E is an enlarged top plan view of an essentialportion showing the stress concentrated portion of the structure shownin FIG. 6D, after broken.

[0083] As shown in FIG. 5 and FIGS. 6A and 6B, the easily broken portion37 is gradually thinned in the thickness directions (normal to theDrawing) and in the circumferential directions from both the first fixedportion 33 and the second fixed portion 35 to the others, to form astress concentrated portion 55 in its intermediate portion. The stressconcentrated portion 55 is sectionally formed into a rectangularsectional shape, as shown in FIG. 6B, because its molding structure issimplified. However, the sectional shape of the stress concentratedportion 55 should not be limited to the rectangular sectional shape, buta circular section or another could be arbitrarily selected. Moreover,the easily broken portion 37 is formed by thinning it gradually in boththe thickness directions and the circumferential directions. However,the stress concentrated portion 55 could also be formed by thinning itgradually only in the thickness or circumferential directions.

[0084] The breaking strength of the easily broken portion 37 is setlower than the crushing strength against the press-fittings of theprotrusions 43 of the outer press-fit portions 41 into outerpress-fitting accommodating portions 63 and the press-fittings of theprotrusions 51 of the inner press-fit portions 49 into innerpress-fitting accommodating portions 71. In other words, the crushingstrength of the individual press-fit portions is set higher than that ofthe easily broken portion 37.

[0085] The accommodating portion 31 and its periphery are made, as shownin FIG. 7 and FIG. 8. FIG. 7 is a top plan view showing theaccommodating portion 31 and its periphery, and FIG. 8 is an enlargedsectional view taken in arrows SC-SC of FIG. 7. As shown in FIG. 7 andFIG. 8, the accommodating portion 31 is formed between an inwardcircumference 57 and an outward circumference 65. The inwardcircumference 57 is formed on the side of the terminal block 3 and isformed into a circular shape concentric to the fitting hole 24 of themoving block 7. The first fixed portion 33 is closely fitted at itsouter circumference in the inward circumference 57, which confronts theouter circumference of the first fixed portion 33. The outwardcircumference 65 is formed on the side of the moving block 7 and isformed into a concentric circular shape as the outer circumference ofthe boss portion 23. The second fixed portion 35 is closely fitted atits inner circumference on the outward circumference 65, which confrontsthe inner circumference of the second fixed portion 35.

[0086] On the outer circumference of the accommodating recess 31, thereare formed a pair of outer fastening accommodating portions 59. Theseouter fastening accommodating portions 59 accommodate the outerfastening portions 39 and are made slightly shallower than theaccommodating recess 31. In the outer fastening and accommodatingportions 59, there are protruded protrusions 61 for thermallyadditionally fastening purposes.

[0087] On the outer circumferential side of the accommodating recess 31,there are further formed the outer press-fitting accommodating portions63. These outer press-fitting accommodating portions 63 are provided infour to correspond to the outer press-fit portions 41. Twocircumferential sides of the outer press-fitting accommodating portion63 are formed into engaging faces 63 a. When the outer press-fitportions 41 are accommodated in the outer press-fitting accommodatingportions 63, the engaging faces 63 a confront the circumferential sideportions 41 a of the outer press-fit portions 41 closely and press-fitthe protrusions 43 between the engaging faces 63 a.

[0088] The boss portion 23 is equipped with a pair of inner fasteningaccommodating portions 67. These inner fastening accommodating portions67 accommodate the inner fastening portions 47 of the tack-fasteningmember 29. In the inner fastening accommodating portions 67, there areformed protrusions 69 for thermally additionally fastening protrusions69.

[0089] In the boss portion 23, there are further formed the innerpress-fitting accommodating portions 71. These inner press-fittingaccommodating portions 71 are provided in four to correspond to theinner press-fit portions 49 of the tack-fastening member 29. On the twocircumferential sides of each inner press-fitting accommodating portion71, there are formed engaging faces 71 a. When the inner press-fitportions 49 are accommodated in the inner press-fitting accommodatingportions 71, the engaging faces 71 a confront the circumferential sideportions 49 a of the inner press-fit portions 49 closely and press-fitthe protrusions 51 between the engaging faces 71 a.

[0090] Here will be described the tack-fastening operations of theterminal block 3 and the moving block 7. These operations are performedby accommodating the tack-fastening member 29, as shown in FIG. 4 andFIG. 5, in the side of the accommodating recess 31 of FIG. 7 and FIG. 8.For this accommodation, the terminal block 3 and the moving block 7 areadjusted to a specific shift position of the automatic transmission,e.g., to a relative rotational position for detecting an N-position. Inthis state, the tack-fastening member 29 is fitted on the side of theaccommodating portion 31. The tack-fastening member 29 has nodirectivity in its thickness direction so that it can be fitted in theaccommodating recess 31 from the front or back side. Therefore, thisfitting work can be easily done. By this fitting work, the outerfastening portions 39 are accommodated in the outer fasteningaccommodating portions 59, and the inner fastening portions 47 areaccommodated in the inner fastening accommodating portions 67. Thethermally additionally fastening protrusions 61 and 69 are fitted in thethrough holes 39 a and 47 a of the outer fastening portions 39 and theinner fastening portions 47. By thermally additionally fastening theprotrusions 61 and 69, the outer fastening portions 39 are fastened andfixed in the outer fastening accommodating portions 59, and the innerfastening portions 47 are fastened and fixed in the inner fasteningaccommodating portions 67.

[0091] Simultaneously with this, the outer press-fit portions 41 of thefirst fixed portion 33 are accommodated in the outer press-fittingaccommodating portions 63, and the inner press-fit portions 49 of thesecond fixed portion 35 are accommodated in the inner press-fittingaccommodating portions 71. At this time, these accommodations can beeasily effected by the chamfers 45 and 53 of the tack-fastening member29. At these accommodations, the protrusions 43 of the outer press-fitportions 41 are press-fit between the engaging faces 63 a of the outerpress-fitting accommodating portions 63, and the protrusions 51 of theinner press-fit portions 49 are press-fit between the engaging faces 71a of the inner press-fitting accommodating portions 71.

[0092] By these operations, the tack-fastening member 29 can beaccommodated without any looseness in the accommodating recess 31. Inthis case, the outer press-fitting accommodating portions 63, the outerfastening accommodating portions 59, the inner press-fittingaccommodating portions 71, the inner fastening accommodating portions 67and the accommodating recess 31 are opened to the outer faces of theterminal block 3 and the moving block 7 so that the tack-fasteningmember 29 can be easily mounted.

[0093] This tack-fastened state is shown in FIG. 1, FIG. 2 and FIG. 3.In this tack-fastened state, the inhibitor switch 1 is assembled withthe automatic transmission. Specifically, the moving block 7 in thetack-fastened state is fitted at its fitting hole 24 on the manual shaftat a specific shift position such as at the N-position. Next, bolts areinserted into the slots 19 and 21 of the bracket 15 to fasten and fix iton the housing side of the automatic transmission. As a result, theinhibitor switch 1 is completely mounted.

[0094] At this mounting time, the bracket 15 on the side of the case 5may invite an assembling error for each product with respect to theaccurate positioning of the terminal block 3 and the moving block 7 bythe tack-fastening member 29. The dislocation of the bracket 15 withrespect to the automatic transmission due to such error can be absorbedin the slots 19 and 21. Specifically, the fitting hole 24 of the movingblock 7 is fitted on the manual shaft, and the bolts are inserted intothe slots 19 and 21 of the bracket 15 and are fastened as they are. As aresult, the accurate positioning can be made to the N-position of themanual shaft of the automatic transmission with respect to the temporaryfixing state of the N-position of the terminal block 3 and the movingblock 7.

[0095] After the inhibitor switch 1 was assembled, the manual shaftrotates accordingly as the shift lever is moved to be inspected. At thistime, the individual easily broken portions 37 are easily broken at theset torque. These easily broken portions 37 are provided in plurality inthe circumferential directions between the first and second fixedportions 33 and 35. Therefore, the easily broken portions 37 can beindividually made so thin that they can be reliably broken at the settorque while suppressing their flexibility.

[0096] The strengths against the press-fittings of the protrusions 43 ofthe outer press-fit portions 41 into outer press-fitting accommodatingportions 63 and the press-fittings of the protrusions 51 of the innerpress-fit portions 49 into inner press-fitting accommodating portions 71are set higher than the breaking strength of the easily broken portions37. As a result, the easily broken portions 37 can be reliably brokenwithout inviting any looseness in the press-fittings, while fixing thetack-fastening member 37 reliably on the terminal block 3 and the movingblock 7 by the press-fittings.

[0097] When the easily broken portions 37 are broken, the first fixedportion 33 and the second fixed portion 35 are to be individuallydeformed inward. However, the first and second fixed portions 33 and 35are supported and prevented from being deformed by the inwardcircumference 57 and the outward circumference 65, so that the easilybroken portions 37 can be accurately broken at the set torque bytransmitting the breaking force reliably to it.

[0098] The outer and inner press-fit portions 41 and 49 are protruded atpositions different from those of the outer and inner fastening portions39 and 47 so that they can be restrained from the thermal influences ofthe thermally additionally fastenings of the outer fastening portions 39and the inner fastening portions 47 and so that the outer press-fitportions 41 and the inner press-fit portions 49 can be refrained fromthe looseness due to the thermal influences. Therefore, the easilybroken portions can be reliably broken.

[0099] The broken state is shown in FIG. 6C.

[0100] When the manual shaft rotates, as described hereinbefore, thesecond fixed portion 35 rotates with respect to the first fixed portion33. As a result, a shearing force in the rotational direction acts onthe easily broken portion 37. At this time, the shearing stress isconcentrated at the stress concentrated portion 55 of the easily brokenportion so that the stress concentrated portion 55 is broken, as shownin FIG. 6C. These broken faces 37 a and 37 b can be extended in thecircumferential directions by setting the stress concentrated portion55.

[0101] After broken, the portion on the side of the broken face 37 a andthe portion on the side of the broken face 37 b individually shrinkaccording to the properties of the resin so that the broken faces 37 aand 37 b leave each other slightly.

[0102] After shipping, therefore, when the user operates the shift leverto make a speed change, the manual shaft rotates So that the first fixedportion 33 rotates with respect to the second fixed portion 35. At thistime, the broken faces 37 a and 37 b can be prevented from abuttingagainst each other. With this structure, it is possible to eliminate therepetitions of the state, in which a plurality of broken faces 37 a and37 b are simultaneously brought by the rotations into contact with eachother, and the state, in which they are kept away from contact, and toprevent the fluctuation of the operation torque from being caused at theshifting time after broken by the tack-fastening member 29.

[0103] When the stress-concentrated portion is not formed at an easilybroken portion 37A, as shown in FIG. 6D, on the contrary, broken faces37Aa and 37Ab may be inclined, as shown in FIG. 6E. In this case, at therotating time of the manual shaft, the broken faces 37Aa and 37Ab areliable to abut against each other to invite the fluctuation of theoperation torque. By providing the aforementioned stress concentratedportion 55, therefore, the broken faces 37 a and 37 b can be formed inthe circumferential directions, as shown in FIG. 6C, to prevent thefluctuation of the operation torque without fail.

[0104] Even if the broken faces 37 a and 37 b are slightly inclined toabut against each other at the rotating time, moreover, the easilybroken portions 37 are provided in plurality at different spacings sothat they can be made to abut once only at one place while all beingprevented from simultaneously abutting during of rotation of 360°.Therefore, the cases of all abutments and no abutment of the individualbroken faces 37 a and 37 b are not repeated so that the operation torquecan be suppressed from fluctuating.

[0105] It is naturally possible to adopt the structure of the easilybroken portion 37A, as shown in FIG. 6D. Even if the broken faces 37Aaand 37Ab might be inclined in this case, as shown in FIG. 6E, the easilybroken portions 37A can be made to abut one by one in the rotation byproviding them at different spacings in the circumferential directions,so that all of them can be prevented from simultaneously abutting tosuppress the fluctuation of the operation torque.

[0106] After the tack-fastening member 29 was broken, too, the firstfixed portion 33 keeps the state, in which it is fixed on the side ofthe terminal block 3 by thermally additionally fastening it, and thesecond fixed portion 35 keeps the state in which it is fixed on the sideof the moving block 7 by thermally additionally fastening it. Therefore,the fixed portions 33 and 35 can be prevented from coming out toeliminate accumulation of dust. Even if the tack-fastening member 29should come out after broken, it would go out of the inhibitor switch 1to keep the inhibitor switch 1 out from any trouble.

[0107] Thus, at the time of mounting the inhibitor switch 1, there isrequired no special positioning work using a jig or the like, and theinhibitor switch 1 can be accurately assembled in an extremely easymanner with the automatic transmission.

[0108] Here, in the foregoing embodiment, the tack-fastening member 29is mounted in advance between the terminal block 3 and the moving block7. However, the tack-fastening construction can be modified by mountingthe tack-fastening member 29 in advance between the case 5 and themoving block 7 and between both the case 5 and the terminal block 3 andthe moving block 7. Moreover, the outer and inner fastening portions 39and 47 are thermally additionally fastened but may be fastened by screwsor the like. The stress concentrated portion 55 can also be formed byforming a circumferential groove at the easily broken portion 37A ofFIG. 6D.

What is claimed is:
 1. A positioning method of an inhibitor switchincluding a switch housing having a terminal block having stationarycontacts and a cover, and a moving block fitted on a manual shaft of anautomatic transmission and having moving contacts for rotating withrespect to the switch housing, the inhibitor switch being fixed on thehousing of the automatic transmission for detecting the shift positionof the automatic transmission electrically from a relative rotationalposition relation between the stationary contacts and the movingcontacts in accordance with the rotation of the manual shaft of theautomatic transmission, which comprises: temporarily fastening theswitch housing and the moving block in advance, before the inhibitorswitch is fixed on the automatic transmission, through easily brokenportions to be broken at a set torque, at relative rotation positionsfor detecting a specific shift position of the automatic transmission;fixing the inhibitor switch on the automatic transmission after themoving block in the temporarily fastened state was fitted on the manualshaft at the specific shift position; and then releasing the temporarilyfastened state by rotating the manual shaft to break the easily brokenportions.
 2. A positioning structure of an inhibitor switch including aswitch housing having a terminal block having stationary contacts and acover, and a moving block fitted on a manual shaft of an automatictransmission and having a fitting hole and moving contacts for rotatingwith respect to the switch housing, the inhibitor switch being fixed onthe housing of the automatic transmission for detecting the shiftposition of the automatic transmission electrically from a relativerotational position relation between the stationary contacts and themoving contacts in accordance with the rotation of the manual shaft ofthe automatic transmission, which comprises: a tack-fastening memberfastened between the switch housing and the moving block in advance,before the inhibitor switch is fixed on the automatic transmission, atrelative rotation positions for detecting a specific shift position ofthe automatic transmission and adapted to be broken at a set torque,wherein: the moving block is brought into a temporarily fastened statewith respect to the switch housing, after the moving block in thetemporarily fastened state was fitted on the manual shaft at thespecific shift position, the inhibitor switch is fixed on the automatictransmission, and the temporarily fastened state is then released byrotating the manual shaft to break the easily broken portions.
 3. Apositioning structure of an inhibitor switch including a switch housinghaving a terminal block having stationary contacts; and a moving blockfitted on a manual shaft of an automatic transmission and having afitting hole and moving contacts for rotating with respect to theterminal block, the inhibitor switch being fixed on the housing of theautomatic transmission for detecting the shift position of the automatictransmission electrically from a relative rotational position relationbetween the stationary contacts and the moving contacts in accordancewith the rotation of the manual shaft of the automatic transmission,which comprises: a tack-fastening member fastened between the terminalblock and the moving block in advance, before the inhibitor switch isfixed on the automatic transmission, at relative rotation positions fordetecting a specific shift position of the automatic transmission andadapted to be broken at a set torque, wherein: the moving block isbrought into a temporarily fastened state with respect to the terminalblock, after the moving block in the temporarily fastened state wasfitted on the manual shaft at the specific shift position, the inhibitorswitch is fixed on the automatic transmission, and the temporarilyfastened state is then released by rotating the manual shaft to breakthe easily broken portions.
 4. A positioning structure of an inhibitorswitch according to claim 3, wherein the tack-fastening member is madeof a resin and includes a first fixed portion to be fixed on the side ofthe terminal block, a second fixed portion to be fixed on the side ofthe moving block, and an easily broken portion for connecting the firstand second fixed portions.
 5. A positioning structure of an inhibitorswitch according to claim 4, wherein the first and second fixed portionsare formed into a ring shape generally concentric to the fitting hole ofthe moving block; and the easily broken portion is provided in pluralityin the circumferential directions between the first and second fixedportions.
 6. A positioning structure of an inhibitor switch according toclaim 4 or 5, wherein the first fixed portion is equipped with an outerpress-fit portion; the second fixed portion is equipped with an innerpress-fit portion; the terminal block is equipped with an outputpress-fitting accommodating portion for press-fitting the outputpress-fit portion; the moving block is equipped with an innerpress-fitting accommodating portion for press-fitting the innerpress-fit portion; and each of the press-fit portions has a crushingstrength set higher than the strength of the easily broken portions. 7.A positioning structure of an inhibitor switch according to claim 6,wherein the terminal block is equipped with an inward circumference forconfronting the outer circumference of the ring-shaped first fixedportion; the moving block is equipped with an outward circumference forconfronting the inner circumference of the ring-shaped second fixedportion; and an accommodating recess for accommodating the first andsecond fixed portions is formed between the inward circumference and theoutward circumference.
 8. A positioning structure of an inhibitor switchaccording to claim 6 or 7, wherein the first fixed portion is equippedseparately of the outer press-fit portion with outer fastening portionsto be fastened and fixed on the side of the terminal block; the secondfixed portion is equipped separately of the inner press-fit portion withinner fastening portions to be fastened and fixed on the side of themoving block; the outer fastening portions are thermally additionallyfastened and fixed on the side of the terminal block; and the innerfastening portions are thermally additionally fastened and fixed on theside of the moving block.
 9. A positioning structure of an inhibitorswitch according to claim 7, wherein the outer press-fittingaccommodating portions, the inner press-fitting accommodating portionsand the accommodating recess are opened to the outer faces of theterminal block and the moving block.
 10. A positioning structure of aninhibitor switch according to any of claims 4 to 9, wherein the easilybroken portions are interposed in plurality at different spacings in thecircumferential directions between the first and second fixed portions.11. A positioning structure of an inhibitor switch according to any ofclaims 4 to 10, wherein the easily broken portions are gradually thinnedfrom both of the first fixed portion and the second fixed portion to theothers to form stress-concentrated portions at their intermediateportions.